Magnetic and Thermoelectric Properties of Fe–Ti–Sn Alloys

The magnetic and thermoelectric properties of Fe
_3-x
Ti
_x
Sn (x = 0-1) alloys were investigated. The Fe
_3-x
Ti
_x
Sn (x = 0.5-1) alloys consisted of the Fe
₂
TiSn Heusler phase, while the Fe
_3-x
Ti
_x
Sn (x = 0-0.25) alloys contained the Fe
₃
Sn phase together with the FeSn
₂
and Fe phases. Although the Fe
₂
TiSn specimen showed the low saturation magnetization, the Fe
₃
Sn specimen exhibited the high saturation magnetization. It was found that the Curie temperature of the Fe
₂
TiSn phase was around 350 K. Thermoelectric property measurements revealed that the Fe
₃
Sn specimen was an n-type thermoelectric material, whereas the Fe
₂
TiSn specimen was a p-type thermoelectric material. The highest power factor of 317 μW/mK
²
was obtained in the Fe
₂
TiSn specimen, but this value was smaller than that of the Fe
₂
VAl Heusler compound. This was due to the fact that the Seebeck coefficient of the Fe
₂
TiSn specimen was lower than the value expected from a first-principles study.